1. Technical Field
The present disclosure relates to loudspeakers and, particularly, to a carbon nanotube based loudspeaker.
2. Description of Related Art
Loudspeakers are apparatus that reproduce sound recorded in different media. The loudspeaker commonly includes an enclosure (i.e., housing, box, or cabinet) and a sound wave generator disposed in the enclosure. The loudspeakers can be divided into passive loudspeakers and active loudspeakers. The active loudspeakers are any loudspeakers that contain their own amplifiers (e.g. those for computers or i-pods), or loudspeakers that divide the frequencies for each sound wave generator before power-amplification, using an active crossover. The passive loudspeakers are loudspeakers without amplifiers.
The enclosure generally is a shell structure defining a hollow space therein, made of wood, ceramic, plastic, resin, or other suitable material. The sound wave generator inside the enclosure is used to transform an electrical signal into a sound pressure that can be heard by human ears.
There are different types of sound wave generators that can be categorized according by their working principle, such as electro-dynamic sound wave generators, electromagnetic sound wave generators, electrostatic sound wave generators and piezoelectric sound wave generators. However, the various types ultimately use mechanical vibration to produce sound waves, in other words they all achieve “electro-mechanical-acoustic” conversion. Among the various types, the electro-dynamic sound wave generators are most widely used.
Referring to FIG. 19, a typical passive loudspeaker 10 according to the prior art with an electro-dynamic sound wave generator 100, includes an enclosure 110. The sound wave generator 100 is disposed in the enclosure 110. The sound wave generator 100 is mounted on a front panel of the enclosure 110. The sound wave generator 100 includes a voice coil, a magnet and a cone. The voice coil is an electrical conductor, and is placed in the magnetic field of the magnet. By applying an electrical current to the voice coil, a mechanical vibration of the cone is produced due to the interaction between the electromagnetic field produced by the voice coil and the magnetic field of the magnets, thus producing sound waves. However, the structure of the electric-powered sound wave generator 100 is dependent on magnetic fields and often weighty magnets.
Carbon nanotubes (CNT) are a novel carbonaceous material and have received a great deal of interest since the early 1990s. Carbon nanotubes have interesting and potentially useful electrical and mechanical properties, and have been widely used in a plurality of fields.
What is needed, therefore, is to provide a loudspeaker having a CNT structure that is not dependent on magnetic fields.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one exemplary embodiment of the present loudspeaker, in at least one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.